Endoscope

ABSTRACT

An endoscope has a first bending portion and a second bending portion. The first bending portion is the distal portion of an elongated insertion member, and the second bending portion is located at the proximal end of the first bending portion. The dimension of the second bending portion in the longitudinal axis of the insertion member is smaller than the dimension of the first bending portion therein. The endoscope includes a hand-held unit having a control section that is used to bend the first bending portion and second bending portion. The control section of the hand-held unit has an angling knob that is used to bend the first bending portion, and a second angling lever that is used to bend the second bending portion.

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2000-302470, filed on Oct. 2,2000 and No. 2001-232166 filed on Jul. 31, 2001 in Japan, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope, or more particularly, toan endoscope having two bending portions of a first bending portion anda second bending portion.

2. Description of the Related Art

Endoscopes have an elongated insertion member thereof inserted into athree-dimensionally complexly tortuous and narrow lumen of the stomach,the intestine, or any other organ of a living tissue, or athree-dimensionally complexly tortuous and narrow hollow of a machine inconformity with the shape of the lumen or hollow. The insertion membermust therefore be angled three-dimensionally finely.

For example, an endoscope described in Japanese Examined PatentApplication Publication No. 5-16857 has two bending portions of a firstbending portion and a second bending portion. The first bending portionis the distal portion of an elongated insertion member and has aplurality of joint pieces concatenated so that the joint pieces canrotate freely. The second bending portion is located at the proximal endof the first bending portion. A hand-held unit having a control sectionthat is used to bend the first bending portion and second bendingportion has an angling mechanism. The sole angling mechanism enablesselective bending of the first bending portion and second bendingportion.

However, when the insertion member of an endoscope has two bendingportions, the lengths of the bending portions have a significantmeaning.

For example, assume that a narrow lumen such as the lumen of the largeintestine is observed. In this case, if the second bending portion thatis the proximal portion is longer, when the second bending portion isbent, the bending portion including the first and second bendingportions is entirely largely moved. It is therefore hard to finelyadjust the position of the distal part of the endoscope. This eventuallyposes a problem that observation is hard to achieve.

For example, when the cardia of the stomach and its surroundings areobserved by viewing the face of the cardia, the first bending portion islargely bent in an Up direction and the second bending portion is bendin a Down direction. The distal part of an endoscope may thus be made toapproach the cardia. When the second bending portion is long, althoughthe second bending portion has not fully come out of the esophagus, thewhole bending portion including the first and second bending portionsmust be bent. It is therefore hard to bend the second bending portion.This results in unsuccessful observation.

The present invention attempts to break through the foregoing situation.The present invention aims to provide an endoscope capable of offeringimproved ease of observation with a second bending portion thereof bentand with a distal portion of an insertion member thereof faced a desiredposition.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide anendoscope offering improved ease of observation with a distal portion ofan insertion member thereof faced a desired position.

Another object of the present invention is to provide an endoscopehaving two bending portions that can be bent independently of eachother, and offering ease of bending of the same level as that anendoscope having one bending portion offers.

Still another object of the present invention is to provide an endoscopeoffering excellent maneuverability and making it possible to readilyachieve accurate observation or treatment.

According to the present invention, there is provided an endoscopehaving a first bending portion and a second bending portion. The firstbending portion is the distal portion of an elongated insertion member.The second bending portion is located at the proximal end of the firstbending portion. The dimension of the second bending portion in thelongitudinal direction of the insertion member is smaller than thedimension of the first bending portion therein.

According to the present invention, there is provided an endoscopehaving a first bending portion, a second bending portion, a firstcontrol member, and a second control member. The first bending portionis the distal portion of an elongated insertion member. The secondbending portion is located at the proximal end of the first bendingportion, and the dimension of the second bending portion in thelongitudinal direction of the insertion member is smaller than thedimension of the first bending portion therein. The first control memberis included in a hand-held unit proximal to the insertion member andused to bend the first bending portion. The second control member isincluded in the hand-held unit proximal to the insertion member and usedto bend the second bending portion.

Other features of the present invention and the advantages thereof willbe fully apparent from the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the overall configuration of an endoscope system includingan endoscope in accordance with an embodiment of the present invention;

FIG. 2 is a sectional view showing a bending portion of an insertionmember included in the endoscope shown in FIG. 1;

FIG. 3A and FIG. 3B are explanatory diagrams showing bending piecesincluded in a first bending portion and a second bending portionrespectively;

FIG. 3A is an explanatory diagram showing a bending piece included inthe first bending portion;

FIG. 3B is an explanatory diagram showing a bending piece included inthe second bending portion;

FIG. 4 is an explanatory diagram showing the structure of a coil pipe;

FIG. 5 shows the appearances of a hand-held unit of the endoscope andits surroundings;

FIG. 6 is an explanatory diagram showing the hand-held unit of theendoscope shown in FIG. 5 and held with a hand;

FIG. 7 shows the appearance of a hand-held unit of an endoscope that hasan angling knob, which is used to manipulate the second bending portion,included in a second control subsection, and the appearance of itssurroundings;

FIG. 8 shows the appearance of a hand-held unit of an endoscope having afirst control subsection and a second control subsection in which theaxes of rotation cross at a right angle, and the appearance of thesurroundings of the hand-held unit;

FIG. 9 shows the appearance of a hand-held unit of an endoscope that hastwo angling knobs included in a second control subsection, and theappearance of its surroundings;

FIG. 10A to FIG. 10C are plan views showing other examples of an anglingknob included in the second control subsection;

FIG. 11 shows the appearance of another example of the angling knobincluded in the second control subsection;

FIG. 12 is an explanatory diagram showing an insertion member having abending portion composed of a first bending portion and a second bendingportion by which bending angles are assumed when bent are set;

FIG. 13 is an explanatory diagram showing movements made by theinsertion member shown in FIG. 12;

FIG. 14 is an explanatory diagram showing other movements made by theinsertion member shown in FIG. 12;

FIG. 15A to FIG. 15C are explanatory diagrams showing the bendingportion shown in FIG. 12 and adapted to other endoscopes;

FIG. 15A is an explanatory diagram showing the insertion member of aconventional enlarged-view endoscope;

FIG. 15B is an explanatory diagram showing the insertion member of aconventional endoscope having two forceps passage channels;

FIG. 15C is an explanatory diagram showing the insertion member of theenlarged-view endoscope shown in FIG. 15A or the endoscope having twoforceps passage channels as shown in FIG. 15B, wherein the insertionmember has the bending portion shown in FIG. 12;

FIG. 16A and FIG. 16B are explanatory diagrams showing an insertionmember that has a second bending portion thereof made shorter than afirst bending portion thereof;

FIG. 16A shows an explanatory diagram showing the insertion member whosesecond bending portion is shorter than the first bending portionthereof;

FIG. 16B is an explanatory diagram showing a case where the insertionmember shown in FIG. 16A is inserted into a tortuous lumen;

FIG. 17A to FIG. 17C are explanatory diagrams showing a case where anendoscope is used to observe the cardia of the stomach and itssurroundings;

FIG. 18A and FIG. 18B are explanatory diagrams showing an insertionmember that has a first bending portion thereof made shorter than asecond bending portion thereof;

FIG. 18A is an explanatory diagram showing the insertion member whosefirst bending portion is shorter than the second bending portionthereof;

FIG. 18B is an explanatory diagram showing a case where the insertionmember shown in FIG. 18A is inserted in a lumen that is hardly curved;

FIG. 19 is an explanatory diagram showing a case where an insertionmember characterized in that the number of the directions in which asecond bending portion thereof is bent is limited to a minimum necessarynumber of directions is inserted in a lumen in which only a specificobject can be observed;

FIG. 20A to FIG. 20C are explanatory diagrams showing angulation wiresthat are arranged at positions in the second bending portion that ensureeasy bending in oblique directions;

FIG. 20A is a sectional view showing angulation wire locks included inthe second bending portion in order to lock two second wires that arearranged at an Up position and a Right position;

FIG. 20B is a sectional view showing angulation wire locks included inthe second bending portion in order to lock two second wires that arearranged at Down and Left positions;

FIG. 20C is a sectional view showing angulation wire locks included inthe second bending portion in order to lock two second wires that arearranged at an intermediate position between Up and Right positions andan intermediate position between Down and Left positions;

FIG. 21 is an explanatory diagram showing the insertion member of aconventional endoscope whose bending portion is composed of a firstbending portion and a second bending portion;

FIG. 22 is a schematic explanatory diagram showing an insertion memberwhose bending portion includes a second bending portion that can bestraightened; and

FIG. 23 is a schematic explanatory diagram showing an insertion memberthat is a variant of the insertion member shown in FIG. 22.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described with referenceto the drawings below.

FIG. 1 to FIG. 9 are concerned with an embodiment of the presentinvention.

As shown in FIG. 1, an endoscope system 1 having the embodiment of thepresent invention consists mainly of an electronic endoscope(hereinafter simply an endoscope) 2, a light source apparatus 3, a videoprocessor 4, and a monitor 5. The electronic endoscope 2 has an imagepick-up means that is not shown. The light source apparatus 3 isconnected to the endoscope 2 so that it can be disconnected freely, andsupplies illumination light to the endoscope 2. The video processor 4 isconnected to the endoscope 2 so that it can be disconnected freely. Thevideo processor 4 controls the image pick-up means included in theendoscope 2 and processes a signal produced by the image pick-up meansto transmit a standard video signal. The monitor 5 displays anendoscopic image according to a signal processed by the video processor4.

A VTR deck, a video printer, a video disk drive, an image file recordingapparatus, or the like, not shown, can be connected to the videoprocessor 4.

The endoscope 2 has an elongated insertion member 11 that is insertedinto a region to be observed. A hand-held unit 12 is located at theproximal end of the insertion member 11. The hand-held unit 12 includesa control section 12 a that is used to bend first and second bendingportions that will be described later.

A universal cord 13 is extended from the lateral side of the hand-heldunit 12. A signal cable that is routed to the image pick-up means whichis not shown and a light guide over which illumination light ispropagated are contained in the universal cord 13.

A connector 14 is attached to the end of the universal cord 13. Theconnector 14 is coupled to the light source apparatus 3 and connected tothe video processor 4 such that it can be connected and disconnectedfreely.

A distal part 21 is located at the distal end of the insertion member11. A bending portion 22 capable of freely bending is located at theproximal end of the distal part 21. A flexible-tube 23 is located at theproximal end of the bending portion 22. The flexible tube 23 is formedwith an elongated member that is soft and tubular.

An image pick-up unit in which a solid-state image pick-up device thatis not shown, such as, a CCD and a circuit board for driving thesolid-state image pick-up device are incorporated is included as theimage pick-up means in the distal part 21. The distal end of the lightguide is extended to the distal part 21, whereby illumination lightpropagated from the light source apparatus 3 is radiated to a region tobe observed in a body cavity. The region to be observed is thusilluminated.

The bending portion 22 is composed of two bending portions, that is, afirst bending portion 24 that is the distal half of the bending portion22 and a second bending portion 25 that succeeds the first bendingportion 24.

To begin with, the structure of the bending portion 22 will be describedin conjunction with FIG. 2 to FIG. 5.

As shown in FIG. 2, the first bending portion 24 and second bendingportion 25 each has a plurality of bending pieces 31 concatenated sothat the bending pieces can rotate freely. The plurality of bendingpieces 31 are sheathed with a bending braid 32 made by cylindricallyweaving thin wires. The bending braid 32 is sheathed with a bendingrubber 33 and thus kept watertight.

The bending braid 32 and bending rubber 33 may be used to sheathe thebending portion 22 composed of the first bending portion 24 and secondbending portion 25 over the whole length of the bending portion 22.Otherwise, the first bending portion 24 and second bending portion 25may be sheathed with the bending braid 32 and bending rubber 33independently of each other.

First wires 34 used to pull and bend the first bending portion 24 areextended from the distal end of the first bending portion 24.

Second wires 35 used to pull and bend the second bending portion 25 areextended from the distal end of the second bending portion 25.

The first wires 34 are passed through first coil pipes 36 fixed to thedistal end of the second bending portion 25, and thus routed to a firstcontrol subsection 42, which will be described later, by way of theinsertion member 11.

Moreover, the second wires 35 are passed through second coil pipes 37fixed to the distal end of the flexible tube 23, and thus routed to asecond control subsection 44, which will be described later, by way ofthe insertion member 11.

Furthermore, the thickness of the portion of the bending rubber 33 withwhich the second bending portion 25 is sheathed is smaller than thethickness of the portion thereof with which the first bending portion 24is sheathed. Consequently, the second bending portion of the bendingportion 22 is more easily bent. Even if a larger number of built-incomponents must be put in the second bending portion 25, the outerdiameter of the second bending portion 25 need not be increased. Theease of bending characterizing the bending portion 22 will therefore notdeteriorate.

Generally, when the bending portion 22 is bent, a larger load is oftenimposed on the second bending portion 25 than on the first bendingportion 24. This is because the second bending portion 25 accommodates alarger number of built-in components.

For this reason, the bending pieces 31 constituting the second bendingportion 25 of the bending portion 22 are, as shown in FIG. 3A and FIG.3B, made thicker than those constituting the first bending portion 24.

In other words, bending pieces 31 b used to construct the second bendingportion 25 of the bending portion 22 as shown in FIG. 3B are madethicker than bending pieces 31 a used to construct the first bendingportion 24 as shown in FIG. 3A.

Consequently, even when a larger magnitude of force is applied to thesecond bending portion 25 than to the first bending portion 24, thebending pieces 31 constituting the second bending portion 25 hardlydeform. Thus, a bending angle the second bending portion 25 assumes whenbent is set will not get smaller than a bending angle it assumes in aninitial state.

Moreover, coil pipes used as the first coil pipes 36 and second coilpipes 37 are made by, as shown in FIG. 4, finely winding a thin wire sothat adjoining portions of the wire will be closely in contact with eachother. Owing to this structure, the whole length of the coil pipe may beshortened with application of a load of compression. For this reason,the diameter of a wire used to make the second coil pipes 37 fixed tothe proximal end of the second bending portion 25 that must incur alarger load is made larger than the diameter of a wire used to make thefirst coil pipes 36. Consequently, the second coil pipes 37 are hardlycompressed because they are made using a thicker wire than the firstcoil pipes 36 are. Therefore, even if a larger magnitude of force isapplied to the second bending portion 25 than to the first bendingportion 24, the coil pipes will not contract. Thus, a bending angle thesecond bending portion assumes when bent is set will not get smallerthan the one it assumes in an initial state.

According to the present embodiment, the control section 12 a of thehand-held unit 12 consists of the first control subsection 42 and secondcontrol subsection 44. The first control subsection 42 is used to bendthe first bending portion 24. The second control subsection 44 is usedto bend the second bending portion 25. Owing to the structure, the firstbending portion 24 and second bending portion 25 can be bentindependently of each other.

The first control subsection 42 includes, as shown in FIG. 5, anglingknobs 42 a and 42 a′ and first locking levers 42 b and 42 b′. Theangling knobs 42 a and 42 a′ are used to bend the first bending portion24. The first locking levers 42 b and 42 b′ are used to lock the anglingknobs 42 a and 42 a′ at desired angular positions.

The second control subsection 44 includes, as shown in FIG. 5, a secondangling lever 44 a used to bend the second bending portion 25 and asecond locking lever 44 b used to lock the second angling lever 44 a ata desired angular position.

The control section 12 a has an electric switch subsection 43 thatincludes remote switches 43 a used to instruct the video processor 4 tofreeze or unfreeze a view image.

The angling knob 42 a is a knob used to bend the first bending portion24 in Up and Down directions. The angling knob 42 a′ is a knob used tobend the first bending portion 24 in Right and Left directions.

The first locking lever 42 b is a lever used to lock the angling knob 42a at a desired angular position. The first locking lever 42 b′ is a knobused to lock the angling knob 42 a′ at a desired angular position.

Furthermore, the first control subsection 42 includes anaeration/perfusion button 42 c used to instruct aeration or perfusionand a suction button 42 d used to instruct suction.

The endoscope 2 having the foregoing components is used to performendoscopic examination.

In general, an operator holds, as shown in FIG. 6, the hand-held unit 12with his/her left hand so as to angle the endoscope.

In this case, for example, the hand-held unit 12 is borne with the rootof the thumb of the left hand and the ring finger and little finger ofthe left hand. The angling knob 42 a and second angling lever 44 a aremanipulated using the thumb. The index finger and middle finger are alsoused to manipulate the angling knob 42 a and second angling lever 44 awhen these fingers are not manipulating the remote switches 43 a and thebuttons including the aeration/perfusion button 42 c and suction button42 d.

When an operator wants to bend the first bending portion 24, theoperator bears the hand-held unit 12 with the root of the thumb of theleft hand and the ring finger and little finger thereof. The operatorthen manipulates the angling knob 42 a using the thumb, index finger, ormiddle finger thereof. At this time, the angling knob 42 a lies withinreach of the thumb, index finger, or middle finger.

Moreover, when an operator wants to bend the second bending portion 25,the operator manipulates the second angling lever 44 a with his/herright hand that does not hold the hand-held unit 12.

The thumb, index finger, or middle finger may be stretched to a positionthat is usually beyond reach of it in order to manipulate the secondangling lever 44 a.

When the remote switches 43 a are used or endoscopic treatment iscarried out, the first locking levers 42 b and 42 b, and the secondlocking lever 44 b may be used to lock the angling knobs 42 a and 42 a,and the second angling lever 44 a at desired angular positions. In thiscase, the thumb can be separated from the hand-held unit, and theendoscope can be manipulated with the insertion member retained in adesired bent state.

Moreover, the second control subsection 44 is separated from the firstcontrol subsection 42 with the electric switch subsection 43 betweenthem. When the angling knob 42 a is manipulated, the fingers with whichthe angling knob is manipulated will not come in contact with the secondangling lever 44 a.

The second angling lever 44 a may be, as shown in the plan view of FIG.10A, jutted out in a direction opposite to the direction of the anglingknobs 42.

The foregoing structure may be modified in consideration of ease withwhich the second angling lever 44 a can be manipulated with, forexample, the right hand, so that the second angling lever 44 a will jutout towards the angling knobs 42 as shown in FIG. 10B and FIG. 10C.

Referring to FIG. 5 and FIG. 6, the second angling lever 44 a that is alever used to bend the second bending portion 25 is included in thesecond control subsection 44. However, the present invention is notlimited to the second angling lever 44 a. As shown in FIG. 7, when thesecond bending portion can be bend in freely selected directions, anangling knob 44 c that resembles the angling knob 42 a may besubstituted for the second angling lever 44 a.

The axes of rotation in the first control subsection 42 and secondcontrol subsection 44 may extend parallel to each other as shown in FIG.5. Alternatively, the axes of rotation may meet at an angle as shown inFIG. 8. Referring to FIG. 8, the axes of rotation in the first controlsubsection 42 and second control subsection 44 cross at right angles.

Moreover, when the second bending portion 25 is designed to be able tobend in four directions, the second control subsection 44 includes twoangling knobs 44 c as shown in FIG. 9. The second bending portion 25 canthus be bent in four directions.

Consequently, in the endoscope 2 in accordance with the presentembodiment, the first and second bending portions 24 and 25 can be bentindependently of each other. The two bending portions can be handled inthe same manner as an ordinary bending portion is. The endoscope 2 ofthe present embodiment offers improved ease of bending.

The endoscope 2 of the present embodiment has the second controlsubsection 44 separated from the first control subsection 42.Consequently, when the first control subsection 42 alone is used, thesecond control subsection will not annoy an operator. The endoscopeoffers ease of bending of the same level as a normally employedendoscope having one bending portion does.

Furthermore, the endoscope 2 of the present embodiment has the secondcontrol subsection 44 and first control subsection 42 separated fromeach other with the electric switch subsection 43 between them.Consequently, the maneuverability offered by the endoscope will not bepoorer than the maneuverability offered by an ordinary endoscope. Inaddition, when the first control subsection 42 and electric switchsubsection 43 are used, the second control subsection 44 will not bemanipulated incorrectly.

In the endoscope 2 of the present embodiment, the axes of rotation inthe first control subsection 42 and second control subsection 44 meet atan angle. Consequently, when the first control subsection 42 is heldwith one hand and the second control subsection 44 is manipulated withthe other hand, the second control subsection 44 can be manipulatedeasily.

The endoscope 2 in accordance with the present embodiment is anelectronic endoscope having the image pick-up unit incorporated in thedistal part 21 of the insertion member 11. Alternatively, the presentinvention may be implemented in an electronic endoscope in which animage guide that is not shown is run through the insertion member 11 andan object image propagated along the image pick-up guide is picked up byan image pick-up unit incorporated in the control section 12 a.Moreover, the present invention may be implemented in a so-calledoptical endoscope in which an object image propagated along the imageguide is viewed through an eyepiece unit mounted on the control section12 a. In any case, the endoscope has the bending portion 22 composed ofthe first bending portion 24 and second bending portion 25.

The present invention is not limited to the aforesaid embodiment, butcan be modified in various aspects with the gist of the presentinvention left unchanged.

For example, as shown in FIG. 11, the second angling lever 44 a may belocated at a position at which a forceps lift lever is usually-locatedin an ordinary endoscope.

As far as observation of an intracavitary region is concerned, observinga region to be observed from the front side thereof is very helpful in aviewpoint of producing a clear image devoid of deformation.

When an endoscope has the same structure as the aforesaid one, that is,the elongated insertion member 11 has the bending portion 22 composed ofthe first bending portion 24 and second bending portion 25, the firstbending portion 24 and second bending portion 25 are bent independentlyof each other. Thus, the distal part 21 of the insertion member can befaced a region to be observed.

For example, the insertion member 11 may be in close contact with theintracavitary wall as shown in FIG. 21. In this case, the second bendingportion 25 is bent upward by an angle θ with respect to the longitudinalaxis of the insertion member 11. At the same time, the first bendingportion 24 is bent downwards by an angle θ+90° with respect to thelongitudinal axis of the insertion member 11. Consequently, the distalpart 21 of the insertion member 11 is angled to face a region to beobserved that is located on an intracavitary wall.

FIG. 21 is an explanatory diagram showing the insertion member of aconventional endoscope having a bending portion composed of a firstbending portion and a second bending portion.

However, assume that the insertion member 11 is in close contact with anintracavitary wall, and that the distal part 21 of the insertion memberis faced the intracavitary wall. In this case, the distal part 21 islocated near an extension of the longitudinal axis of the flexible tube23 (which is in close contact with the intracavitary wall) of theinsertion member 11. Consequently, the distal part 21 cannot have apredetermined distance from the region to be observed.

If the distal part 21 cannot be separated from a region to be observedby a predetermined distance, it is hard to observe the region to beobserved during endoscopic examination. Although the predetermineddistance cannot be preserved, if an attempt is made to performendoscopic treatment, a therapeutic instrument or the like may not beable to be projected from the distal part 21 towards an intracavitarywall. Consequently, the endoscopic treatment fails.

In order to solve the above problem, it is conceivable to increase thedimension of the second bending portion 25. The second bending portion25 is bent appropriately in order to raise the first bending portion 24relative to the intracavitary wall, whereby the predetermined distancemay be preserved. However, this structure has a drawback that theoverall length of the bending portion 22 is too large.

The bending portion 22 has, as described in conjunction with FIG. 2, theplurality of bending pieces 25 sheathed with the braid 32 and bendingrubber 33. The surface of the bending portion 22 is therefore finelyirregular and hardly smooth. The bending portion 22 must therefore havea minimum necessary length.

There is therefore a long-persistent demand for an endoscope that offersimproved ease of observation and treatment when the distal part 21 isfaced an intracavitary wall with both the first bending portion 24 andsecond bending portion 25 bent.

Referring to FIG. 12 to FIG. 20C, an example of the structure of anendoscope including two bending portions will be described below.

FIG. 12 to FIG. 20C show the example of the structure of an endoscopeincluding two bending portions.

As shown in FIG. 12, the first bending portion 24 and second bendingportion 25 are bent, and the distal part 21 of the insertion member isthus angled in a direction perpendicular to the longitudinal axis of theinsertion member 11, that is, faced an intracavitary wall. In thisstate, bending angles the first bending portion 24 and second bendingportion 25 that constitute the bending portion 22 assume when bent isset are determined so that the distal part 21 will always lie above anextension of the longitudinal axis of the insertion member 11 (so thatthe distal part 21 can be distanced from a region to be observed).

Referring to FIG. 12, the bending angle the second bending portion 25assumes when bent, θ, is set substantially to 90° and the bending anglethe first bending portion 24 assumes when bent, (θ+90°), is setsubstantially to 180°.

The thus-structured bending portion 22 is adapted to a conventionalenlarged-view endoscope 2A that has, as shown in FIG. 15A, an imagepick-up unit (not shown), of which focus can be changed from one toanother, incorporated in the distal part 21. Otherwise, the bendingportion 22 is adapted to a conventional endoscope 2B having, as shown inFIG. 15B, two forceps passage channels 51.

As shown in FIG. 15A, the conventional enlarged-view endoscope 2A hasthe insertion member 11 that includes one bending portion. Therefore,the distal part 21 is located on or near an extension of thelongitudinal axis of the flexible tube 23 (that is in close contact withan intracavitary wall) along the intracavitary wall. It is thereforehard to observe a lesion located tangentially to the intracavitary wall.

Referring to FIG. 15B, a predetermined distance cannot be preservedbetween the distal part 21 of the insertion member of the endoscope 2Bhaving two forceps passage channels 51 and a region to be observed. Atherapeutic instrument 52 or the like cannot be projected from thedistal part 21. It is therefore hard to perform endoscopic treatment.

Now, when the bending portion 22 is structured as shown in FIG. 12, thedistance between the distal part 21 and a region to be observed can beadjusted as shown in FIG. 15c. Moreover, two therapeutic instruments canbe used for endoscopic treatment.

As shown in FIG. 13, when a lesion is observed, the first bendingportion 24 and second bending portion 25 are bent, and the secondlocking lever 44 b is manipulated in order to lock the second anglinglever 44 a at a desired angular position. Consequently, the secondbending portion 25 can be retained in a desired bent state. The firstbending portion 24 is bent vertically and laterally with the secondangling-lever 44 a locked. Eventually, the distal part of the endoscopecan be angled in the directions of arrows with the lesion and distalpart distanced from each other.

In short, observation can be continued with the relative positions ofthe lesion and the distal part varied.

Furthermore, as shown in FIG. 14, the first locking levers 42 b and 42b′ are manipulated to lock the bending knobs 42 at desired angularpositions. Consequently, the first bending portion 24 is retained in adesired bent state. In this state, the second bending portion 25 is bendin two directions. Thus, the distal part of the endoscope can be angledin the directions of arrows while faced the lesion.

In short, the distance between the lesion and the distal part of theendoscope can be adjusted with the distal part angled to the lesion.

As shown in FIG. 13 and FIG. 14, the first bending portion 24 and secondbending portion 25 can be retained in respective bent states. This leadsto improved ease of manipulation offered for endoscopic observation.

Furthermore, the bending portion 22 may be designed such that the secondbending portion 25 will be shorter than the first bending portion 24 asshown in FIG. 16A. For example, when the endoscope is used to observe atortuous lumen such as the lumen of the large intestine, even if thesecond bending portion 25 is bent, the second bending portion 25 willnot interfere with the intestinal wall but the bending portion 22 can beentirely moved.

In contrast with FIG. 16A, FIG. 18A shows the bending portion having thesecond bending portion 25 made longer than the first bending portion 24.As shown in FIG. 18B, when the bending portion is inserted in a lumenthat is almost not at all curved, for example, the lumen of the stomach,ease of insertion or treatment can be improved. Namely, a therapeuticinstrument can be inserted easily during endoscopic treatment, or thedistal part 21 of the insertion member can be angled easily finely.

As shown in FIG. 17A, when an endoscope has only one bending portion,the bending portion can be bent in order to position the distal partclosely to the cardia of the stomach. However, the cardia and itssurroundings are observed obliquely. It is therefore hard to view thecardia and its surroundings from the front sides thereof.

As shown in FIG. 17B, when the second bending portion 25 is somewhatlong, since the second bending portion 25 must be fully jutted out ofthe esophagus, the first bending portion 24 recedes from the cardia ofthe stomach. Therefore, even if an attempt is made to bend the firstbending portion in order to observe the cardia and its surroundings, thedistance between the distal part of the endoscope and the cardia is toolarge to achieve observation successfully.

Now, in an endoscope shown in FIG. 17C, the dimension of the secondbending portion 25 in a direction of insertion is smaller than thedimension of the first bending portion 24 therein. When the dimensionsof the first and second bending portions 24 and 25 in the direction ofinsertion are thus set, if the first and second bending portions 24 and25 are bent in order to observe the cardia of the stomach and itssurroundings, the distal part of the endoscope can be positioned closelyto the cardia. This results in successful observation.

As shown in FIG. 19, an endoscope may be used exclusively to observe,for example, the duodenum. In this case, the second bending portion 25is made bendable in only one direction (an Up or Down direction). Likethis, the number of the bendable directions of the second bendingportion 25 is limited to a minimum necessary number of directions. Thisleads to a simplified angling mechanism.

FIG. 19 shows a case where the distal part 21 of the insertion member ismade to approach the duodenal papilla.

When the duodenal papilla or any other region of the duodenum isincised, the distal end of an endoscope should be made to approachobliquely for more successful treatment.

In this case, the second wires 35 to be pulled in order to bend thesecond bending portion 25 may be arranged as shown in FIG. 20A to FIG.20C.

As shown in FIG. 20A and FIG. 20B, the second wires 35 lying through thesecond bending portion 25 may be arranged at Up and Right positions orDown and Left positions so that the second bending portion 25 can beeasily bent obliquely.

As shown in FIG. 20C, the second wires 35 lying through the secondbending portion 25 may be arranged at an intermediate position betweenthe Up and Right positions and an intermediate position between the Downand Left positions.

As far as the aforesaid endoscope whose elongated insertion member 11has the bending portion 22 is concerned, the second bending portion 25of the bending portion 22 is first bent. Namely, the one of the secondwires 35 described in conjunction with FIG. 2, which is located at theUp position, is pulled in order to bend the second bending portion 25 inthe Up direction. If the second bending portion 25 is straightenedthereafter, since restoring force exerted by the bending rubber 33 withwhich the second bending portion 25 is sheathed is weak, the one of thesecond wires 35 which is located at the Down position must be pulled.Therefore, an angling mechanism is very complex.

There is therefore a demand for an endoscope having a simple structureand having the second bending portion 25 capable of being straightened.

Referring to FIG. 22 and FIG. 23, an example of the structure of anendoscope whose second bending portion can be straightened will bedescribed below.

As shown in FIG. 22, the first bending portion 24 of the bending portion22 has a plurality of bending pieces 31 concatenated so that the bendingpieces can rotate freely. The concatenated bending pieces 31 aresheathed with the bending braid 32 made by cylindrically weaving thinwires, and then covered with the bending rubber 33.

The second bending portion 25 has, similarly to the first bendingportion 24, the plurality of bending pieces 31 concatenated so that thebending pieces can rotate freely. The bending pieces 31 are sheathedwith the bending braid 32. The bending braid 32 is coated with aresilient resin 61 such as polyester which is the same resin as thatadopted for the flexible tube 23.

Consequently, the second bending portion 25 has the bending braid 32coated with the resilient resin 61 that is the same resin as thatadopted for the flexible tube 23. Therefore, the second bending portion25 that has been bent can be straightened by merely slackening one ofthe second wires 35. Namely, the second wire 35 to be slackened is asecond wire that has been pulled in order to bend the second bendingportion 25 in a direction that runs externally parallel to the secondwire.

Moreover, the second wires 35 used to bend the second bending portion 25may lie, as shown in FIG. 23, alone at one position, so that the secondbending portion 25 can be bent in only one direction.

As described in conjunction with FIG. 2, the second wires 35 are passedthrough the second coil pipes 37 inside the flexible tube 23 up to theproximal end of the second bending portion 25.

The second bending portion 25 has the same structure as, for example,the flexible tube 23 (for example, as shown in FIG. 22, molded using thesame resin 61 as that adopted for the flexible tube 23). Thus, thesecond bending portion 25 is easily straightened.

Consequently, when the second wires 35 are not tensioned, the secondbending portion 25 is automatically straightened. Only one of the secondwires 35 can therefore be used to bend or straighten the second bendingportion 25. Herein, a position of the second wire defines one directionin which the second bending portion 25 can be bent.

The present invention is not limited to the aforesaid embodiment, butcan be modified in various aspects with the gist of the invention leftunchanged.

As described so far, according to the present invention, a secondbending portion is made shorter than a first bending portion. Thisresults in an endoscope that can be angled readily while beingunaffected by the state of a lumen into which the endoscope is inserted.

According to the present invention, it is apparent that a wide range ofdifferent embodiments can be formed based on the invention without adeparture from the spirit and scope of the invention. The presentinvention is limited to the appended claims but not restricted to anyspecific embodiment.

What is claimed is:
 1. An endoscope comprising: a first bending portionthat is the distal portion of an elongated insertion member, the firstbending portion being bendable in accordance with the bending operationby a user; and a second bending portion that is located at the proximalend of said first bending portion and whose dimension in thelongitudinal direction of said insertion member is smaller than that ofthe first bending portion, the second bending portion being bendable inaccordance with the bending operation by a user; wherein a bending anglesaid first bending portion assumes when bent is set and a bending anglesaid second bending portion assumes when bent is set are determined sothat when said second bending portion is bent by an angle θ and saidfirst bending portion is bent by an angle θ+90° or more in a directionopposite to the direction in which said second bending portion is bent,if the distal portion of said insertion member is angled substantiallyperpendicularly to the longitudinal direction of said insertion member,the distal portion of said insertion member will be distanced from atangent to the longitudinal direction of said insertion member.
 2. Theendoscope according to claim 1, wherein: said first bending portion canbe bent in four directions substantially perpendicular to thelongitudinal direction of said insertion member; and said second bendingportion can be bent in at least two directions perpendicular to thelongitudinal direction of said insertion member.
 3. The endoscopeaccording to claim 1, wherein a bending angle the first bending portionassumes when bent is set is larger than a bending angle the secondbending portion assumes when bent is set.
 4. An endoscope according toclaim 3, wherein said second bending portion is passively bendable infour directions substantially perpendicular to the longitudinaldirection of said insertion member.
 5. The endoscope according to claim3, wherein the directions in which said second bending portion isbendable are agreed with two directions out of the directions in whichsaid first bending portion is bendable, said two directions are oppositeto each other.
 6. An endoscope comprising: a first bending portion thatis the distal portion of an elongated insertion member; a second bendingportion that is located at the proximal end of said first bendingportion and whose dimension in the longitudinal direction of saidinsertion member is smaller than the dimension of the first bendingportion therein; a first control portion included in a hand-held unitproximal to said insertion member and used to bend said first bendingportion; and a second control portion included in the hand-held unitproximal to said insertion member and used to bend said second bendingportion; wherein a bending angle said first bending portion assumes whenbent is set and a bending angle said second bending portion assumes whenbent is set are determined so that when said second bending portion isbent by an angle θ and said first bending portion is bent by an angleθ+90° or more in a direction opposite to the direction in which saidsecond bending portion is bent, and when the distal portion of saidinsertion member is angled substantially perpendicularly to thelongitudinal direction of said insertion member, the distal portion ofsaid insertion member will be distanced from a tangent to thelongitudinal direction of said insertion member.
 7. The endoscopeaccording to claim 6, wherein: said first bending portion is bendable infour directions substantially perpendicular to the longitudinaldirection of said insertion member; and said second bending portion isbendable in at least two directions perpendicular to the longitudinaldirection of said insertion member.
 8. The endoscope according to claim6, wherein said first control portion is included in the distal part ofa control section, and said second control portion is included in theproximal part of the control section.
 9. The endoscope according toclaim 6, wherein a bending angle said first bending portion assumes whenbent is set is larger than a bending angle said second bending portionassumes when bent is set.
 10. The endoscope according to claim 6,wherein said second bending portion is passively bendable in fourdirections substantially perpendicular to the longitudinal direction ofsaid insertion member.
 11. The endoscope according to claim 6, whereinthe directions in which said second bending portion is bendable areagreed with two directions out of the directions in which said firstbending portion is bendable, said two directions are opposite to eachother.
 12. The endoscope according to claim 6, wherein the axis ofrotation of said first control portion and the axis of rotation of saidsecond control portion are extended in different directions.
 13. Theendoscope according to claim 6, wherein: said first control portion islocated so that when said hand-held unit is held, said first controlportion will lie within reach of a finger of the hand with which saidhand-held unit is held; and said second control portion is located sothat when said hand-held unit is held, said second control portion willlie beyond reach of a finger of the hand with which said hand-held unitis held.
 14. The endoscope according to claim 6, wherein an electricswitch subsection used to give predetermined instructions is interposedbetween said first control portion and said second control portion. 15.The endoscope according to claim 6, wherein said first control portionis located in the distal part of a control section, and said secondcontrol portion is located in the proximal part of the control section.16. The endoscope according to claim 6, wherein said first controlportion is arranged so that when said hand-held unit is held, said firstcontrol portion will lie within reach of a finger of the left hand withwhich said hand-held unit is held; and said second control portion isarranged so that when said hand-held unit is held, said second controlportion will lie beyond reach of a finger of the left hand with whichsaid hand-held unit is held, and will be manipulated with a finger ofthe right hand.
 17. The endoscope according to claim 6, wherein saidfirst control portion includes a first Right/Left control member that isused to bend said first bending portion in a Right or Left direction,and a first Up/Down control member that is used to bend said firstbending portion in an Up or Down direction.
 18. The endoscope accordingto claim 6, wherein said second control portion includes a secondUp/Down control member that is used to bend said second bending portionin an Up or Down direction.
 19. The endoscope according to claim 12,wherein the axis of rotation of said first control portion and the axisof rotation of said second control portion are extended substantiallyparallel to each other.
 20. The endoscope according to claim 12, whereinthe axis of rotation of said first control portion and the axis ofrotation of said second control portion are extended substantiallyperpendicularly to each other.
 21. The endoscope according to claim 14,wherein said electric switch subsection separates said first controlportion and said second control portion from each other.
 22. Theendoscope according to claim 15, wherein a manipulated portion of saidfirst control portion and a manipulated portion of said second controlportion face in the same direction.
 23. An endoscope comprising: a firstbending portion that is the distal portion of an elongated insertionmember, the first bending portion being bendable in accordance with thebending operation by a user; and a second bending portion that islocated at the proximal end of the first bending portion and whosedimension in the longitudinal direction of the insertion member islarger than that of the first bending portion, the second bendingportion being bendable in accordance with the bending operation by auser.
 24. An endoscope comprising: a first bending portion that is thedistal portion of an elongated insertion member; a second bendingportion that is located at the proximal end of said first bendingportion and whose dimension in the longitudinal direction of saidinsertion member is larger than the dimension of the first bendingportion therein; a first control portion included in a hand-held unitproximal to said insertion member and used to bend said first bendingportion; and a second control portion included in the hand-held unitproximal to said insertion member and used to bend said second bendingportion.
 25. The endoscope according to claim 18, wherein the secondcontrol portion further includes a second right/left control member thatis used to bend the second bending portion in a Right or Left direction.26. The endoscope according to claim 1, wherein the first bendingportion is bendable under the control of a first control portion; andthe second bending portion is bendable under the control of a secondcontrol portion.
 27. The endoscope according to claim 6, the firstcontrol portion and the second control portion are located in differentpositions.
 28. The endoscope according to claim 27, wherein the firstcontrol portion is arranged so that when the hand-held unit is held, thefirst control portion will lie within reach of a finger of the hand withwhich the hand-held unit is held; and the second control portion isarranged so that when the hand-held unit is held, the second controlportion will lie beyond reach of a finger of the hand with which thehand-held unit is held.
 29. The endoscope according to claim 26, whereinthe first bending portion can be bent in four directions substantiallyperpendicular to the longitudinal direction of the insertion member; andthe second bending portion can be bent in at least two directionsperpendicular to the longitudinal direction of the insertion member. 30.The endoscope according to claim 26, wherein a bending angle the firstbending portion assumes when bent is set is larger than a bending anglethe second bending portion assumes when bent is set.
 31. The endoscopeaccording to claim 26, wherein the second bending portion is passivelybent in four directions substantially perpendicular to the longitudinaldirection of the insertion member.
 32. The endoscope according to claim26, wherein the direction in which the second bending portion is bentare arranged with two directions in which the first bending portion isbent, the two directions are opposite to each other.
 33. The endoscopeaccording to claim 1, wherein said second bending portion accommodates alarger number of built-in components than said first bending portion.34. The endoscope according to claim 6, wherein said second bendingportion accommodates a larger number of built-in components than saidfirst bending portion.
 35. The endoscope according to claim 23, whereinsaid second bending portion accommodates a larger number of built-incomponents than said first bending portion.
 36. The endoscope accordingto claim 24, wherein said second bending portion accommodates a largernumber of built-in components than said first bending portion.
 37. Anendoscope comprising: a first bending portion that is the distal portionof an elongated insertion member, the first bending portion beingbendable in accordance with the bending operation by a user; and asecond bending portion that is located at the proximal end of saidbending portion, the second bending portion being bendable in accordancewith the bending operation by the user, wherein said second bendingportion has its length different from that of said first bending portionand a bending angle said first bending portion assumes when bent is setand a bending angle said second bending portion assumes when bent is setare determined so that when said second bending portion is bent by anangle θ and said first bending portion is bent by an angle θ90° or morein a direction opposite to the direction in which said second bendingportion is bent, if the distal portion of said insertion member isangled substantially perpendicularly to the longitudinal direction ofsaid insertion member, the distal portion of said insertion member willbe distanced from a tangent to the longitudinal direction of saidinsertion member.
 38. The endoscope according to claim 37, wherein saidsecond bending portion accommodates a larger number of built-incomponents than said first bending portion.